The Atthasalini (II, Part II, 400) explains about being unguarded as to the
“controlling faculties,” the indriyas. Here, the indriyas of eyes, ears, nose, tongue,
body-sense and mind are referred to. We read:

“Grasps the general appearance,

i.e., grasps by way of lusting,

desire a sign such as is of the male,

or female, pleasant, etc.,

and which is the basis of corruption.”

When we cling to the general appearance of male or female, it shows that the
object is not a paramattha dhamma. When we know that we see a man or woman,
we don’t just know the reality that appears through the eyes, but we have an
image (nimitta), a concept on account of what appears through the eyes. The
image of the general appearance of a man or woman is the foundation of
defilements. Through the power of desire (chanda raga) we take that image for
something attractive. When we like a concept such as a belt, it shows that the belt
is an attractive image. One is attached to it, one is ruled by desire. If the belt is not
beautiful, if it is not an attractive nimitta (image), one does not like it. On account
of colours that appear through the eyes, there can be different nimittas, attractive
or unattractive.

We read further on in the Atthasalini:

Grasps the details (anuvyanjana),

i.e., takes the various modes of hands and feet,

of smiling, laughing, speaking,

looking straight ahead, looking askance,

which have earned the name of “details,”

they manifest, reveal the defilements.

The details are the conditions that cause defilements to appear. When someone
likes a belt he likes the general appearance (the image) and the details. If all belts
were the same, if there were no variety of them, the details would not be different.
However, there are many kinds of belts and they are different as to the details.
The details condition the arising of different kinds of defilements.